Adhesive tape

ABSTRACT

A method of manufacturing rolls of pressure-sensitive adhesive tape without using preformed cores which involves first attaching a nonadhesive liner sheet to tape to be wound and then winding the liner and the tape around a mandrel in such a way that the nonadhesive liner is wound in contact with the mandrel surface and the tape is wound around the liner. The resulting product also is described and claimed.

D United States Patent 1 1 1 1 Hall et al. 1 Aug. 12, I975 [541 ADHESIVE TAPE 2.695,!39 11 1954 Horvath 242/685 2 [75l inventors: Joseph J. Hall, Somerville; Leo M. 3/)66 Ahlcmeyer 229/5 BP Lamb Freehold of FOREIGN PATENTS OR APPLICATIONS [73] Assignee: Johnson & Johnson, New 991.368 5/1965 United Kingdom 206/411 Brunswick, NJ. 73825] 7/l966 Canada 229/51 BP [22] Filed: May 16, [973 Primary Examinerwilliam I. Price [2H App. 360'890 As'sismn! Examiner-Bruce H1 Bernstein Related U.S. Application Data [62] Division of Ser. No. 174141 Aug 25, l97l, Pat. No.

3.770542. [57] ABSTRACT 52] U S C 206/4 r 242/68 242,74 A method of manufacturing rolls of pressure-sensitive adhesive tape without using preformed cores which g gl g g ff involves first attaching a nonadhesive liner sheet to 206/4 l 5' A 6 tape to be wound and then winding the liner and the (H/I45 tape around a mandrel in such a way that the nonadhesive liner is wound in Contact with the mandrel surface and the tape is wound around the liner. The re- UNITE SZZFSIZS SZQFENTS sulting product also is described and claimed. 1.885.587 11/1932 Burton 138/144 2 Claims, 14 Drawing Figures ADHESIVE TAPE This is a division of application Ser. No. 174.747. filed Aug. 25. I971. and now US. Pat. No. 3.770.542.

The present invention relates to a method or process for manufacturing rolls of normally tacky and pressuresensitive adhesive tape wherein the tape is wound upon itself to form an annular roll with the adhesive side of the tape facing inwardly toward the axis of the roll and to the resulting tape roll and more particularly to a pro cess wherein a multiplicity of relatively narrow tapes are slit from a much wider adhesive sheet and individually wound in the form of rolls in this manner.

Herctofore. these tape rolls have been manufactured by winding the slit tapes upon a series of hollow, cylindrical or annular cores which are positioned on a winding mandrel in a specific spaced relation from one another. These cores have been made of cardboard. plastic and even metal. However. they normally are cut from a hollow cardboard tube into narrower cores of the desired axial dimension. in fact. this latter method has proven most useful because adhesive tapes are manufactured in different widths and each core should have substantially the same axial dimension or width as the tape wound thereon. Thus. normally the cardboard cores are cut or slit in advance of the time they are needed to manufacture tape rolls and kept in inventories of various core sizes. i.c.. widths and diameters. Tape rolls also are manufactured in different corc diameters for different uses, principally to facilitate dispensing of the tape from the roll. This means that the cost of maintaining and storing these core inventories must be added to the various core manufacturing costs.

Another problem. in addition to core costs. in winding tape rolls upon cylindrical cores in this manner. is in maintaining axial alignment between the tape being wound and the cores themselves. Misalignmcnt between the tape and the core. not only is unsightly. but can cause roll telescoping and tape dispensing problems. In addition, it should be noted that the loading of cores onto mandrels in modern tape winding apparatus normally requires a high proportion of the time of one man assigned to loading the cores and removing the tape rolls therefrom.

We have invented a method of manufacturing rolls of normally tacky and pressure-sensitive adhesive tape which eliminates the above costs and problems because our process eliminates the need for preformed cylindrical cores. in the process of our invention. the core, if there is one. is formed as the tape is wound in the process of this invention. a flexible and nontacky liner sheet is attached to the leading end of the tacky pressure-sensitive sheet, and the liner and the tape are wound around the mandrel in such a way that the liner envclops the periphery of thc mandrel and the tape envclops the liner prior to winding the remainder ofthe adhesive tape around the mandrel. Thus. the adhesive tape is wound around the liner with its tacky surface in contact with the periphery of the liner so that it holds the liner in position on the mandrel and. with the liner. forms a central cylinder about which the tape is wound around the mandrel.

In our process. the liner is attached to the wide pressure-sensitive adhesive sheet before the adhesive sheet is slit into narrower tapes. and the liner is slit into tapes along with the adhesive sheet prior to advancing the liner and the tapes into engagement with the winding mandrel. Thus. the liner for any particular tape slit is in exact width-wise alignment with that tape prior to reaching the mandrel. Of course. this tape then will remain in alignment with the wound liner during forma tion of the roll. In the preferred form of this invention. adjacent tapes slit from the adhesive sheet are wound alternately on a pair of mandrels, each of which is positioned in a separate rotatable turret which includes winding positions for at least two mandrels, although as many four winding positions sometimes are used. One of the main advantages of this type of turret winding is that empty mandrels are automatically brought into position for winding as the full mandrels are moved out of position by rotation of the turret. ln the process of our invention, the liner is so positioned with respect to the adhesive sheet that it is automatically located so as to be engaged by the empty mandrel when the mandrel is rotated into position as described above.

In the preferred embodiment of this invention, the liner sheet is adhered to the adhesive side of the leading end of the pressuresensitivc adhesive sheet in such a way that the extreme leading end of the adhesive sheet overlaps the leading end of the liner. [t is this leading end of the adhesive sheet which is available to adhere the liner to the mandrel for each of the tapes slit from the sheets. In our preferred process using the rotating turrets described above. the liner sheet corresponding in width with the original adhesive sheet is applied to the under side of the adhesive sheet in timed relation with the desired length of the adhesive sheet or tape which is to be wound into rolls in such a way that the liner will appear at the winding turret adjacent the empty mandrel just as this mandrel is brought into contact with the tape. Then, the tape is cut to release the rolls wound upon the full mandrel and separate them from the new leading tape ends which already are adhering the new liners to the empty mandrel. or more properly to the empty mandrels since two mandrels are used as described above. Then. the trailing ends of the tapes attached to the full rolls are wound about the full mandrel to complete these rolls and the new rolls are begun on the empty mandrels. first by winding the newly adhered liners about the mandrel surface and then by winding the tape, itself, about the liners.

In our preferred process just described. the liner and the tapes are wound on expandable mandrels. These mandrels are in their diametrically expanded position when the liners are attached thereto and the tape is wound about the liner to form the rolls. When it is desired to remove the full rolls from the mandrels. the mandrels are contracted diametrically to provide an annular space between the liner and the circumference of the mandrel. This allows the tape roll and the mandrel to be rotated with respect to one another oppositely to the direction in which the roll was wound to detach the tape from the mandrel and draw it underneath the leading end of the liner and into adhering contact therewith. This clearly releases the tape roll from engagement with the mandrel and exposes only the nonadhcsivc side of the leading end of the tape to the hollow inner circumference of the roll which is otherwise covered by the liner.

Thus. the liner performs the first function of the prior art tape cores. that of shielding the tacky inner circumference of the hollow tape roll, first from the mandrel during manufacture principally so that the rolls can he removed therefrom, and secondly from dirt and handling during use. In addition, the liner. with the first convolution of tape wOLll'ld around the liner and adhered thereto, acts as the central cylinder about which the tape is wound and fixes the inner diameter of the tape roll. This central cylinder may be quite flexible or fairly rigid depending upon the nature of the liner material which is employed. For instance, the liner may be a paper as thin or thinner than the tape backing, in which case its principal function is to act as a shield as described above. On the other hand. the liner may be in the form of a flexible corrugated cardboard laminate of the general type described in US. Pat. No. 2,350,369 so that the central cylinder formed with the first encircling layer of tape possesses considerable rigidity and will retain its shape until that first layer or. in the direction of unwinding, the last convolution of the adhesive tape is removed or unwound from around the liner. In either case, i.e., whether the liner merely is a shield or imparts considerable rigidity to the tape roll, when that convolution of tape in contact with the liner is unwound, the liner itself also is unwound and returned to sheet form.

Thus, the product of our invention, i.e., the pressuresensitive adhesive tape roll wound around the liner, has a decided functional advantage when used in any kind of dispensing equipment which normally would require removal of spent cores when the tape which they carry is all used or unwound therefrom. Since, in the tape roll of this invention, the liner is retained in its cylindrical configuration only by adhesive contact with the tape wound around it, when that tape is unwound the liner also is unwound and therefore may be removed quickly from the axle or winding shaft of the dispensing equipment in which it is mounted.

Other and further objects of the invention will be apparent to one skilled in the art from the following description and claims taken together with the drawings wherein:

FIG. I is a schematic view partly in section and partly in elevation of apparatus for performing the method of this invention, with the apparatus ready to wind the liner material and the tape into rolls.

FIG. 2 is a view similar to FIG. I of the tape winding end of the equipment showing the apparatus in the position it would assume when full tape rolls have been wound on the mandrels and the next length of liner material approaches the winding position.

FIG. 3 is a view similar to FIG. 2 of the same equipment. showing the apparatus just after the turrets supporting the mandrels have been rotated 180 to cause the full mandrels and the empty mandrels to exchange positions and the empty mandrel to enter into engagement with the leading end of the tape overlapping the liners.

FIG. 4 is a view similar to FIG. 3 showing the apparatus just after the trailing end of the tape attached to the full mandrels have been cut and wound thereon and with the liners in position on the empty mandrcls ready for winding into new tape rolls.

FIG. 5 is a portion of a view taken along the line 55 of FIG. I, partly in section and partly in elevation showing how adjacent tapes cut from the same sheet are alternately wound on separate mandrels.

FIG. 6 is a somewhat enlarged view, partly in section and partly in elevation taken along the line 6-6 of FIG. I with the liner material adhered to the under side of the pressure-sensitive adhesive supply sheet.

FIG. 7 is a more greatly enlarged schematic view. partly in section and partly in elevation. of one of the tape winding mandrels in its expanded condition showing how a liner attached to the under side of the tape 5 to be wound on the mandrel is secured to the mandrel for winding purposes through the adhesive under side of the extreme leading edge of the tape which overlaps the liner.

FIG. 7A is an even more greatly enlarged view of the It) encircled portion of FIG. 7, partly in section and partly in elevation, showing the attachment of the liner to the mandrel through the overlapping tape as the mandrel begins to rotate to wind the liner around it.

FIG. 8 is a view similar to FIG. 7 of the same mandrel l5 just after the liner has been wound there-around.

FIG. 8A is a view similar to FIG. 7A of the encircled portion of FIG. 8 showing the relationship of the tape and the liner at the point where the ends of the liner overlap just after the liner has been wound around the 30 mandrel and the tape is about to be wound into a roll around the liner.

FIG. 10 is a view similar to FIG. 8 but showing the tape roll fully wound on the mandrel with the mandrel in its collapsed condition and the extreme leading end of the tape which was adhered to the mandrel bent around and under the corresponding leading end of the liner so that its nonadhesive surface faces inwardly toward the mandrel.

FIG. 9A is a more greatly enlarged view of the encircled portion of FIG. 10 showing the position of the tape and the liner just as the tape roll and the mandrel have begun to be rotated with respect to one another oppositely to the direction in which the roll was wound to draw the leading tape end under the liner and detach it from the mandrel.

FIG. "IA is a view similar to FIG. 9A after the tape end has been fully released from the mandrel and is bent around and under the corresponding leading end of the liner as shown in FIG. I0.

FIG. II is a view similar to FIG. 8A showing a slight modification wherein the liner sheet is somewhat shorter so that its ends do not overlap one another but come into close proximity.

Referring to the drawings. there is shown a large supply roll 31 of a wide sheet of pressure-sensitive adhesive sheet material 32 and a somewhat smaller supply roll 33 of nonadhesive liner material 34 of substantially the same width which are to be fed together to attach selected lengths of the liner material 34 to the adhesive under side of the pressure-sensitive sheet 32. When the terms length and width are used in reference to these sheets, length refers to the dimension in the direction of travel of the sheets and width refers to their dimension at right angles to length and transverse to travel or in an axial direction with reference to the supply rolls. The pressure-sensitive adhesive sheet 32 comprises a backing layer or sheet 35 which presents an adhesive layer 36 on one major surface and is nonadhesive or nontacky on its other major surface. As in most tape rolls of this type. the supply roll 3] is wound with the adhesive side of the sheet facing inwardly toward the axis of the roll and the nonadhcsivc surface of the sheet facing outwardly.

65 The pressure-sensitive adhesive sheet 32 is drawn under and around spaced idling and positioning rollers 37, which contact the nonadhcsive top side of the sheet. by a driven pull roll 38 which contacts the adhesive underside of the sheet. The liner material 34 is drawn from its supply roll 33 and fed in the same direction as the pressure-sensitive adhesive sheet by a pair of intermittently driven feed rollers 39. The feed rollers 39 draw the material around a guide roller 41 and then through the nip between them to feed the desired length of liner material 34 between a pair of spaced horizontal guides 41 into position over a horizontal support. such as a vacuum box lift table 42. One end of the table 42 is adapted to act as an anvil 43 for cooperating with a cutting knife 44 positioned above the liner for cooperative vertical movement with respect to the anvil 43 to sever the desired length from the liner sheet. When this is done. the lift table 42 is raised to press the liner 34 into adhesive contact with the underside of the pressure-sensitive adhesive sheet 32 passing between the positioning rollers 37, shown by the dotted lines in FIG. I and also in FIG. 6. The feeding of the liner sheet 34. the severance of the desired length of liner material and the motion of the lift table 42 to adhere the liner 34 to the pressure-sensitive adhesive sheet 32 all are controlled by conventional timing means to assure that the desired length of liner 34 is adhered to the adhesive sheet at exactly the right point since this affeels the winding of the liner and the adhesive sheet into a tape roll as will be described more fully hereinafter.

Thus. the adhesive sheet 32 with the liner 34 attached to its adhesive underside is drawn around the pull roll 38 as described hereinbefore, and then underneath a driven platen or anvil roll 43. A bank of circular cutting knives 44 is positioned directly under the platen roll 43 in such a way that the knives can be adjusted towards and away from the roll for slitting the pressure-sensitive adhesive sheet and the liner into narrow widths of pressure-sensitive adhesive tape 45. By way of illustration. if the pressure-sensitive adhesive sheet 32 and the liner sheet 34 are about 60 inches in width and it is desired to produce tapes V: inch wide, the sheet will be slit into I tapes all of which then pass around the platen roll 43 and an idler roller 46 adjacent thereto with their non-adhesive surface facing the platen roll 43 and their adhesive surface facing the idler roller 46. Then. as shown most clearly in FIGS. I and 5, adjacent tapes 45 slit from the same sheet 32 are wound alternately on separate mandrels 47 so that there are 60 tapes on each mandrel. and each of the mandrels is rotatably mounted in a separate winding turret 48. The turrets 48. which are identical. are mounted one above the other and controlled so as to operate simultaneously in the same timed relation with respect to the tape being wound.

Each of the turrets 48 is of the type which is conventional in the pressure-sensitive adhesive tape manufacturing industry and comprises a pair of spaced cylindrical heads 49 (only one of which is shown in the drawings) between which the mandrels 47 are supported and mounted for rotation. conventionally. the heads 49 at one end of the turrets contain the drive for indexing the turrets. i.e.. rotating them l8() to transpose the positions of the two mandrels 47, and for engaging and rotating the mandrels 47 once they are in the desired positions. (The driving ends of the turrets are not specifically shown in the drawings). Typically. the turrets may be rotated by a spur and ring gear combination and the mandrels may be driven through a planetary gear train mounted in the driving head of the turrets.

The driven end of the mandrel, not shown. is geared to enter into driving engagement with the planetary gear train when the mandrels are positioned in the driving heads of the turrets 48. As explained hereinbefore in connection with the apparatus for feeding. cutting and lifting the liner material 34, the indexing of the turrets 48, the rotation of the mandrels 47 and the feeding of the adhesive sheet and tapes with the liners attached. all are controlled in timed relation by cams and other means conventionally used for this purpose to perform the process steps which will be described hereinafter.

Similarly. the opposite end of each of the turrets presents retractable air actuated sockets 51 for engaging the opposite end of each of the mandrels 47 after the driving end of the mandrel has been positioned in the driving head at the opposite end of the turret. These air driven sockets 51 may be extended to engage the mandrel 47 and retracted to allow the mandrel to be removed from the turret simply by actuating a pneumatic cylinder 52 which controls the sockets. The mandrcls 47, themselves, are conventional expandable mandrels which are pneumatically actuated by air supplied through the end of the mandrel through a passageway 53 in the air actuated socket 51, as shown in FIG. 5. Thus. the mandrel 47 may be either expanded or collapsed through control of this air supply.

Referring to particular to FIGS. 2-3 and 7-l0A of the drawings. the various steps in winding tape rolls 50 in accordance with this invention are illustrated. FIG. 2 shows the winding apparatus of FIG. 1 just as the tape rolls on the top or winding mandrel have been fully wound and the next liners are moved into position adjacent the wound mandrels. At this point, the pull roll 38 and the platen roll 43 are stopped and locked in position, the winding mandrels 47 are disengaged from their drive. and the turrets 48 are rotated l80 to transpose. or exchange. the top and bottom mandrels in each turret. As the turrets 48 are rotated in this manner. the tape roll 50 on the top mandrel unwinds just enough to allow the mandrels to exchange positions as the empty bottom mandrel swings up into contact with the liner 34 and finally assumes its winding position above the full mandrel. as shown in FIG. 3.

As shown in FIGS. 2 and 3, a transverse cutting bracket 55 is mounted at the ends ofa pair of swinging arms 56 which are pivotally mounted for rotation about the centerline of each of the turrets 48. Normally, the bracket 55 rests against the leading side of the empty mandrel 47 at the bottom of the turret. as shown in FIG. 2, and when the turret is rotated to exchange the mandrels. the bracket 55 is rotated with the turret in such a way that it enters into adhering contact with the underside of the adhesive tape just ahead of the empty mandrel as shown in FIG. 3. Then, the tape extending across this bracket is severed by a transversely moving knife or other cutting device and the bracket drops down with the tape as the cut trailing end thereof is wound on the full tape roll 50. Finally, the extreme trailing end of the tape is pulled from the bracket 55 and wound on the tape roll as pressure is applied to the roll by the bracket which now rests on top of the roll to wipe it down as shown in FIG. 4. When the full mandrel is removed from the turret so that the tape rolls 50 can be removed from the mandrel, the pivotally mounted bracket again assumes the position shown in FIG 2 on the other side ofa freshly mounted empty mandrel 47.

FIG. 7 shows a winding mandrel 47 in its expanded condition just as the extreme leading end M of a length of adhesive tape 45 to which a liner 34 is attached is brought into adhering engagement with the surface of the mandrel. As soon as this tape end 61 is adhered to the mandrel 47 in this manner. the mandrel is rotated counterclockwise. as shown in FIG. 7A, to begin to wind the liner 34 around and in circumferential contact with the outer cylindrical surface of the mandrel. In the embodiment of FIGS. 7l0A. the length of the liner 34 is slightly greater than the circumference of the mandrel 47 so that the ends of the liner overlap one another slightly when the liner is wound completely around the mandrel. as shown most clearly in FIGS. 8 and 8A. Then the adhesive tape 45 is wound spirally around the mandrel upon itself in successive overlapping convolutions to form a hollow annular cylinder or roll with the adhesive surface of the tape facing inwardly toward the axis of the roll. The liner sheet 34 is adhered to the adhesive surface of the innermost convolution 62 of the tape 45 in such a way that it completely covers the adhesive surface thereof and thereby prevents this surface from adhering to the hand or any other object placed inside the hollow of the roll.

In order to disengage the liner 34 from the mandrel 47 and make it possible to remove the newly wound tape roll 50 therefrom. it is necessary to release the tape or detach it from the mandrel. To accomplish this. the mandrel 47 first is collapsed as shown in FIGS. 9A. I and A. and then the mandrel 47 and the tape roll 50 are rotated with respect to one another in a direction opposite to that in which the tape roll 50 is wound. as indicated by the arrow in FIG. 9A, to detach the tape from the mandrel 47 and bend the leading end 61 around and under the corresponding leading end of the liner 34 as shown most clearly in FIG. 10A. In this configuration, only the nonadhesivc back surface of the extreme leading end 61 of the tape faces inwardly toward the hollow of the roll. As a result. the whole hollow inner surface of the tape roll is effectively shielded against adhesive contact.

FIG. ll illustrates a slight modification of the embodiment of the foregoing figures wherein the liner 34 is slightly shorter than the circumference of the expanded mandrel with the result that the ends of the liner do not overlap and fall just short of abutting relation on the mandrel. While this modification eliminates the slight bump caused by the overlapping liner material. it does not form quite as rigid a structure as that of the foregoing embodiment. The extreme leading end 6| of the tape is disengaged from the mandrel 47 and bent around and underneath the corresponding leading end of the liner 34 after the mandrel has been collapsed as described in connection with FIGS. 9A and IIIA.

It is important to note that in all the embodiments of this invention the liner 34 only is secured in position in the finished tape roll by virtue of its adhesion to the tape with which it is wound and more specifically only through adherence to the innermost convolution 62 of the tape wound around the liner. Thus. when the tape is unwound from the roll down to the last convolution and thus innermost or final convolution finally is unwound the liner 34 automatically is released and unwound at the same time that the tape is unwound. This is an advantage when the tape roll is being used in a dispenser which provides a special axle or post for mounting the tape roll since it eliminates the need to open the dispenser or otherwise provide access thereto only for the purpose of removing a spent tape core therefrom.

Having now described the invention in specific detail and exemplified the manner in which it may be carried into practice. it will be readily apparent to those skilled in the art that innumerable variations. modifications, applications and extensions of the basic principles involved may be made without departing from its spirit or scope. For instance. the liner material may be fed sideways instead of endwise over the air table 42 with a side instead of an end cutoff device to sever the desired length of liner from its supply. Furthermore. the liner could be precut and placed in a stack underneath the pressure-sensitive adhesive sheet and sequentially fed upwardly in timed relation with the adhesive sheet to attach the liners in their proper positions as described hereinbefore. Some of the other possible variations in the nature of the liner material have been discussed hereinbefore.

What is claimed is:

l. A roll of normally tacky and pressure-sensitive adhesive tape. said tape having one of its major surfaces tacky and adhesive and being wound spirally upon itselt in successive axially aligned overlapping convolutions with its adhesive surface facing inwardly toward the axis of the roll to form a hollow annular cylinder, and a liner sheet adhering to the adhesive surface of the innermost convolution of said tape in overlapping relation therewith and having a nonadhesivc surface facing the hollow of said roll. said liner being long enough to effectively cover the inwardly facing adhesive surface of the said innermost convolution of said tape and being unattached to itself except through adherence tc the said innermost convolution. whereby said liner is unwound with said tape as the innermost convolution of the tape is unwound from said roll.

2. A roll of pressure-sensitive adhesive tape accord ing to claim I, wherein the outwardly facing surface 01 said tape is nonadhesivc and the innermost leading end of said tape is bent around and under the corresponding leading end of said lincr. whereby the nonadhesivc surface of said innermost tape end is facing inwardly toward the hollow of said roll. 

1. A roll of normally tacky and pressure-sensitive adhesive tape, said tape having one of its major surfaces tacky and adhesive and being wound spirally upon itself in successive axially aligned overlapping convolutions with its adhesive surface facing inwardly toward the axis of the roll to form a hollow annular cylinder, and a liner sheet adhering to the adhesive surface of the innermost convolution of said tape in overlapping relation therewith and having a nonadhesive surface facing the hollow of said roll, said liner being long enough to effectively cover the inwardly facing adhesive surface of the said innermost convolution of said tape and being unattached to itself except through adherence to the said innermost convolution, whereby said liner is unwound with said tape as the innermost convolution of the tape is unwound from said roll.
 2. A roll of pressure-sensitive adhesive tape according to claim 1, wherein the outwardly facing surface of said tape is nonadhesive and the innermost leading end of said tape is bent around and under the corresponding leading end of saiD liner, whereby the nonadhesive surface of said innermost tape end is facing inwardly toward the hollow of said roll. 